The invention herein is directed to a self-lubricating fill tube. In a particular aspect the self-lubricating fill tube has utility during a procedure for inflating devices through a retention valve.
In the medical field, there are many devices that are utilized which require expansion during use. Many of such devices are inflated either with a gas or liquid to bring about such expansion. The retention valves on such medical devices are constructed to permit the introduction of additional fluid and prevent the escape of the fluid contained in the device. Generally such valves are constructed of a self-sealing rubber and can have configurations such as flap or duckbill valves.
A problem with inflating medical devices is the resistive force encountered during the introduction of a fill tube to the device for delivery of the expansion fluid. The retention valves are generally constructed of rubber such that the operating valve portions of the retention valve are under pressure, which forces the rubber portions together. The pressure exerted to hold the rubber portions together contributes to a relatively high coefficient of friction to the contacting rubber surfaces. Previous fill tubes have been constructed of steel and plastics, such as teflon and polypropylene. These plastics do not significantly overcome the high coefficient of friction of the rubber surfaces through which the fill tube is inserted. Much difficulty has been encountered using teflon and polypropylene fill tubes when trying to introduce the fill tubes through the retention valves of implanted medical devices.
It would be desirable to have a fill tube constructed in such a manner that it would be readily insertable through the retention valve on inflatable medical devices.